Neanderthals and Early Humans May Have Kissing, Researchers Propose

From seabirds to Arctic mammals, chimpanzees to orangutans, certain species engage in mouth-to-mouth contact. Currently, researchers propose that ancient hominins also engaged in this behavior – and might even have locked lips with early Homo sapiens.

Shared Oral Evidence

It is not the first time experts have suggested Neanderthals and early modern humans were closely connected. Among earlier research, researchers have discovered humans and their thick-browed cousins shared the same mouth microbe for hundreds of thousands of years after the evolutionary divergence, suggesting they exchanged oral fluids.

"Probably they were kissing," the researcher noted, adding that the idea aligned with research that has found people of certain genetic backgrounds have bits of ancient genetic material in their genetic makeup, demonstrating genetic mixing was at play.

Intimate Spin

"This offers a different perspective on human-Neanderthal relations," the lead researcher said.

Publishing in the journal a scientific periodical, the researcher and colleagues detail how, to explore the historical roots of intimate contact, they first had to come up with a description that was not restricted by how humans smooch.

Defining Kissing

"Previously there were some previous attempts to define a intimate act, but it's very much been human-centric, which means that essentially non-human species don't kiss. Now we understand that they likely engage, it may appear different from what human kissing resembles," explained Brindle.

Nonetheless, she said some behaviors that looked like kissing were distinct activities – such as the chewing and transfer of food, or "mouth contact", observed in fish called certain marine animals.

Consequently the research group came up with a description of kissing centered around social behaviors involving intentional mouth-to-mouth contact with a member of the same species, with some movement of the oral area but absence of food.

Study Approach

Brindle explained they focused on accounts of kissing in primates from Africa and Asian regions, including bonobos, apes and orangutans, and employed online videos to verify the reports.

The researchers then integrated this information with information on the genetic connections between living and ancient types of such primates.

Evolutionary Origins

The team propose the results indicate kissing developed somewhere between 21.5 million and 16.9 million years ago in the predecessors of the large apes.

Placement of Neanderthals on this evolutionary lineage suggests it is likely they, too, engaged in a intimate act, the researchers conclude. But the activity may not have been confined to their own species.

"Reality that humans engage intimately, the fact that we currently have shown that Neanderthals probably engaged, suggests that the two [species] are probably did engage," the researcher noted.

Evolutionary Significance

While the evolutionary explanation is debated, Brindle said intimate contact could be employed in reproductive situations to possibly enhance mating outcomes or assist in selecting between partners, while it might help strengthen connections when practiced in a non-sexual manner.

Another expert in the behavior of great apes commented that as kissing behavior was seen in a broad spectrum of primates it was logical its roots extend far into our evolutionary past, and an examination of various types of kissing among a broader range of species might extend its beginnings back even earlier still.

"Things that we think of as characteristics of human life, like kissing, are not exclusive to us if we look closely at different species," the expert noted.

Cultural Elements

Another professor explained that kissing had a social component as it was not universal to all societies.

"However, as humans we thrive or fail on the quality of our emotional bonds, and ways of promoting confidence and closeness will have been important for millions of years," she said. "It might be an image that appears a bit contradictory to our incorrect assumptions of a rather ruthless and aggressive past, but really it should be no surprise that Neanderthals – and including them and our own species collectively – engaged intimately."